基于增强型脂质去除固相小柱净化结合液相色谱-串联质谱法测定猪肉和猪肝中的双甲脒农药及其代谢物

建立了采用增强型脂质去除(EMR-Lipid)固相小柱净化结合液相色谱-串联质谱(LC-MS/MS)测定猪肉和猪肝中双甲脒 (AMZ) 及其3种代谢物2,4-二甲基苯胺(DMA)、单甲脒(DMPF)和2,4-二甲基苯基甲酰胺(DMF)残留量的方法。 样品经乙腈蛋白沉淀及盐析提取,通过Captiva EMR-Lipid 过滤小柱净化,滤膜过滤后,采用Agilent ZORBAX Eclipse Plus C₁₈柱(50 mm×2.1 mm,1.8 μm)分离,以0.1%甲酸水溶液与0.1%甲酸乙腈为流动相进行梯度洗脱,采用电喷雾离子源正离子方式扫描,多反应监测模式进行检测。 结果表明,在猪肝与猪肉中AMZ、DMA线性范围为1～200 μg/kg,DMPF和DMF的线性范围为0.1～200 μg/kg,相关系数(R²)均大于0.991;AMZ、DMA、DMPF和DMF的方法定量限(S/N=10)分别为0.6、0.6、0.05、0.05 μg/kg;对空白猪肉和猪肝进行0.1、1、5、50 μg/kg 4个浓度水平的加标实验,回收率在60.2%～127.4%之间,相对标准偏差均低于12%。 该方法简便、快捷,适用于猪肉和猪肝中双甲脒及其代谢物残留量的同时测定。

Simultaneous Determination of Amitraz and Their Metabolites in Pork and Porcine Liver by Enhanced Matrix Removal-Lipid Column Purified/Liquid Chromatography-Tandem Mass Spectrometry

An analytical method based on enhanced matrix removal(EMR)-Lipid column purified/liquid chromatography-tandem mass spectrometry was developed for the determination of amitraz (AMZ) and their metabolites 2,4-xylidine (DMA), semiamitraz (DMPF) and N-(2,4-dimethylphenyl)formamide (DMF) residues in pork and porcine liver. The pork and porcine liver samples were precipitated with acetonitrile and salting out with extraction. The acetonitrile supernatant was cleaned up with Captiva EMR-Lipid cartridge, and then the supernatant solution was filtered through a nylon membrane into a glass LC sample vial for LC-MS/MS analysis. The solution was separated on an Agilent ZORBAX Eclipse Plus column (50 mm×2.1mm, 1.8 μm) with 0.1% formic acid acetonitrile-0.1% formic acid solution as mobile phases by gradient elution, then determined by LC-MS/MS with electrospray ionization (ESI) in positive ion scanning mode under multiple reaction monitoring (MRM) mode. The results show that the linear range of AMZ, DMA in pig liver and pork is 1~200 μg/kg, while the linear range of DMPF and DMF is 0.1~200 μg/kg, The correlation coefficient (R²) is greater than 0.991; The quantitative limits of AMZ, DMA, DMPF and DMF are 0.6, 0.6, 0.05, 0.05 μg/kg, respectively; The spiked recoveries at four levels of 0.1, 1, 5, and 50 μg/kg are in the range of 60.2%~127.4% with relative standard deviations (RSD) lower than 12%. This method provides an easy and fast detection technique for the analysis of AMZ and its metabolites residues in pork and porcine liver samples.